How much should Manny’s stats have dropped? June 8, 2010
Posted by tomflesher in Baseball, Economics.Tags: Baseball, baseball-reference.com, Jim Thome, Manny Ramirez, sports economics, steroids in baseball
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In an earlier post, I used Manny Ramirez‘s differential line to make the case that discontinuing use of performance-enhancing drugs was largely responsible for his drop in production. That’s vulnerable to the criticism that Manny is 38, and that even the best 38-year-old player’s stats drop from his 37-year-old stats.
With that in mind, I queried Baseball-Reference.com’s Play Index to find the stats of players from 1961 to 2009 who, like Manny, played 50% or more of their games in the outfield or as a designated hitter (where Manny might be if he played for an AL team). On average, the 37- and 38-year old players played about 105 games, so I scaled Manny’s drop in stats over the first 27 games to 105 games in order to make the comparison clear. The differential line is behind the cut.
| Age | n | G | PA | AB | R | H |
| 37 | 102 | 103.84 | 389.3 | 340.5 | 51.18 | 93.51 |
| 38 | 75 | 106.3 | 397.3 | 349.2 | 49.32 | 93.87 |
| ∆ | -27 | 2.46 | 8 | 8.7 | -1.86 | 0.36 |
| ∆Manny | x | x | -62.2 | -38.8 | -35 | -19.44 |
| Age | Dbl | Trpl | HR | RBI | BB | IBB |
| 37 | 17.18 | 1.725 | 12.14 | 49.1 | 41.59 | 4.167 |
| 38 | 17.29 | 1.6 | 11.99 | 49.67 | 40.88 | 4.253 |
| ∆ | 0.11 | -0.125 | -0.15 | 0.57 | -0.71 | 0.086 |
| ∆Manny | -11.67 | 0 | -15.5 | 3.89 | -31.11 | -23.33 |
| Age | K | HBP | SH | SF | GDP | SB |
| 37 | 57.02 | 2.961 | 1 | 3.275 | 8.382 | 5.912 |
| 38 | 57.51 | 3.027 | 1.013 | 3.24 | 8.587 | 6.4 |
| ∆ | 0.49 | 0.066 | 0.013 | -0.035 | 0.205 | 0.488 |
| ∆Manny | -15.5 | 0 | 0 | 7.78 | -3.89 | 0 |
| Age | CS | BA | OBP | SLG | OPS | |
| 37 | 2.647 | 0.268 | 0.3461 | 0.4377 | 0.7839 | |
| 38 | 2.267 | 0.2617 | 0.3375 | 0.4139 | 0.7511 | |
| ∆ | -0.38 | -0.0063 | -0.0086 | -0.0238 | -0.0328 | |
| ∆Manny | -3.89 | -0.019 | -0.05 | -0.165 | -0.215 |
Once again, this makes the assumption that nothing besides age and drug use caused Manny’s stats to drop, which may or may not be the case. It also arguably inflates the effect of a slump, in which case a fairer comparison can be made at the end of the season when we can compare full seasons to full seasons. However… this does look damning. Manny’s drops were huge in comparison to the average player’s drops. By comparison, Jim Thome lost .022 in SLG and .018 in OPS, but GAINED .04 in OBP and batting average. He hit 11 fewer home runs playing 25 fewer games, compared with Manny’s larger drop.
Either Manny’s injuries are much more serious than we expect, or the case continues building.
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